Typewriter encoding attachment



July 19, 1966 Filed Sept. 4, 1962 |221@ l: l; :IIS

W. E. EVANS, JR

TYPEWRITER ENCODING ATTACHMENT 4 Sheets-Sheet 1 @l-QU k//u/AM Cyn/vs, J.

INVENTOR.

ATTORNEY July 19, 1966 w. E. EVANS, JR 3,261,914

TYPEWRITER ENCODING ATTACHMENT Filed Sept. 4, 1962 4 Sheets-Sheet 2 INVENTOR. WML/AM E. EVA/vs, .7a.

BY /MMZ July 19, 1966 Filed Sept, 4, 1962 4 Sheets-Sheet 5 SOURCE oF o FERMIN@ POTENTIAL lOl W/L/AM ,5. EVANS/JA.

1NvENToR.

BYM@ my A 70m/5y July 19, 1966 w. E. EVANS, JR 3,261,914

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INVENTOR.

BY im@ A FOAM/Ey United States Patent O Illinois Filed sept. 4, 1962, ser. No. 221,216 Claims. (Cl. 178-81) This invention relates to encoding devices and more particularly to a device which provides electrical code signals corresponding to the characters on a typewriter keyboard.

Various different arrangements have been devised for converting the characters indicated by an actuated typewriter key into an electrical code. These devices have required complex `alterations to a typewriter in order to accommodate and cooperate with the encoding apparatus. The result is an expensive .new typewriter which, .because of the added complications in its structural features requires constant maintenance to prevent breakdowns.

An object of this invention is the provision of a novel attachment for a typewriter whereby it can provide an electrical coded output.

Yet another object of the present invention is the provision of a coding attachment for a typewriter which requires no alterations of the typewriters structure.

Still another object of the present invention is the provision of an inexpensixe and useful encoding attachment for a typewriter.

Yet a further object of the present invention is the provision of a simple encoding attachment for a typewriter which does not affect the normal operation or the maintenance-free life of a typewriter.

These and other objects of the invention may be achieved in an arrangement wherein an encoding attachment is placed beneath a typewriter at a location at which the bell crank levers which are moved by the keys will act-nate the encoding attachment. This encoding attachment comprises effectively, for each typewriter key, a coil bobbin having a hollow center. A magnet extends across the width of the typewriter keyboard and has a pair of co-extensive pole pieces with each one of the bobbins associated with a typewriter character positioned between the two pole pieces. Effectively the cross section of the magnet and its two pole pieces has the shape of a U which lies on its side underneath the row of bell crank levers which are actuated .by the typewriter keys to effectuate printing by the typewriter.

A spring biased pin is positioned underneath each bell crank lever associated with a typewriter key. Each bobbin has the hole therethrough aligned with a hole in the upper and lower pole piece which hole is aligned with a spring biased pin which in turn is positioned beneath a bell crank lever. Thus when a key associated with the bell crank lever is depressed, the bell crank leve-r is pivoted, and in pivoting gives a pin a blow. As a result the pin passes through the 'holes in the upper and lower pole pieces and through the hole in the bobbin. When the bell crank lever returns to its at rest position the spring biased pin is withdrawn from the position to which it was moved. i

Assuming that there are forty-four keys on a typewriter, six wires may be employed to indicate the code for a key which has been depressed. These wires extend in a suitable channel provided therefor and they are selectively Wound around each bobbin. Each wire is then returned to an amplifying device.

To illustrate the coding arrangement, let it be assumed that the letter A is to be represented by a voltage pulse on lines 1, 3 and 5, of the six lines. Thus wires 1, 3

ice

and 5 are each wound with one turn around the bobbin which is' position-ed underneath the bell crank lever actuated when the A key is depressed. When the associated pin is driven into the aligned holes of the pole pieces and the bobbin the magnetic ux which links any wire wound on the bobbin will increase rapidly with the resulting generation of electromotive force in the wires. Thus the amplifiers connected to Vlines 1, 3 and 5 will provide an output and the others will not. Similarily, only lines 2 and 4 can -be coupled to another bobbin whereby it is desired to represent the letter B. When the B typewriter key is struck an associated pin is actuated which causes a voltage to be induced in the lines 2 and 4 which are wrapped around the associated speciedbobbin.

The novel features that are considered characteristic of this invention are set forth with partioularity in theappended claims. The invention itself both as to its organization and method of operation, as well as additional objects and advantages thereof, will be best understood from the following description when read in connection with the accompanying drawings, in which:

FIGURE l is a View in elevation of an embodiment of the invention.

FIGURE 2 is a cross sectional view along the lines 2-2 of FIGURE 1.

FIGURE 3 is a v-iew partly in section showing the embodiment of the invention attached in place on a typewriter.

FIGURE 4 is a circuit diagram showing the arrangement of the six lines employed for encoding connected to six arnpliers, and

FIGURE 5 illustrates a preferred arrangement of the wiring for the embodiment of the invention.

Reference will now be made to FIGURES 1 and 2 which respectively show an elevation View and a cross sectional view along the lines 2 2 of the encoding attachment in accordance with this invention. This invention comprises an arrangement -where'in and when a typewriter key is depressed the associated typewriter linkages `which are activated eventually cause the type character to move toward the typewriter carriage. One of these linkages comprises a bell crank lever which strikes a pin, the pin 'being moved thereby. This pin causes an increase in a magnetic field which is coupled to several wire turns wound on a bobbin, through the center of which the pin passes. Thereby a voltage is induced in these wires. The encoding arrangement is achieved by the presence and absence of pulses of those of the six wires employed for encoding the entire typewriter keyboard.

In one embodiment of the invention six transistors respectively 10, 12, 14, 16, 18, 20, are employed as amplifiers and a different one of the s 'x wires employed for encoding the forty-four keys of the typewriter are connected to each one of these transistors. As may be seen in the cross sectional view of FIGURE 2 the attachment includes a magnet 22 which extends the length of the typewriter keyboard. The magnet has a U shaped cross section and lies on its side. On the back'of the magnet there is supported an elongated plate member 24 which is co-extensive with the magnet. A support member 26 constitutes an elongated block of some suitable nonmagnetic material to which elongated plate member 24 is attached as by several screws 28. An upper and lower pole piece respectively 30, 32 are spaced apart by a nonmagnetic spacer member 31 which maybe made either separately or preferably be formed as part of a wiring insulating board 50. The pole pieces abut the pole faces of the U shaped magnet. Several nonmagnetic bolts 34 are used t'o clamp the pole pieces to the support mem- Patented July 19, 1966 ber, and together with the plate member 24 serve to hold the assembly including the magnet 22 together.

The member 26 has three sides respectively 26A, 26B, 26C which are rectangularly disposed relative to one another and a fourth side 26D which is at an angle with respect to sides 26C and 26A. A support extension 26E connects with the sides 26D and 26A. The support extension 26E has holes therethrough for supporting in each hole a pin 36. A separate pfn is provided for and associated with each typewriter key. The pin has a narrow diameter portion 36A and a wide diameter porlion 36B. The wide diameter portion has one side atted to engage slideably with a holding member 38. The guide member is coextensive with the member 26 and is held thereto by screws 40. The narrow diameter portion of the pin 36A extends into the suitable opening 44 in the upper pole piece member 30. A spring 42 engages the wide diameter -portion 36B of the pin with one end and a narrowed portion of the opening 44, provided -for guiding the pin, with the other end. Accordingly, when the top of the pin, consisting of the wide diameter portion 36B, is given a blow downward, it will move downward compressing the spring thereby, and upon release the spring will return the pin to its initial position.

An opening 46 which is in alignment with the opening 44 for the pin is provided in the lower pole piece 32. A bobbin 48 is inserted between the upper and lower pole piece and is sized to assist in maintaining the spacing of these two pole pieces. The bobbin also has a hole therethrough which is in alignment with those 44, 46, in the upper and lower pole pieces. A wiring insulating board 50, is attached to the upper pole piece by means of screws 52. As previously indicated it may also be held in'place by means of bolts 34. The thickness of the portion of the board which abuts the bobbin is reduced in order to serve as a channel for extending the encoding wires which are employed with the invention.

FIGURE 3 shows the embodiment of the invention in operative association with an electric typewriter 60, such as a Smith-Corona series STE portable electric typewriter. The encoding attachment is placed underneath the typewriter at a location such that each one of the pins 36, wiil be associated with and struck by a bell crank lever 62 which is actuated from the power drive 64, which in turn is actuated when one of the keys 66 is depressed. The bell crank lever 62 is shown in solid line in its at rest position, and in dotted line form when it is actuated by the power drive 64. The lever strikes an associated pin immediately underneath it and moves it downward sufcently to pass through the bobbin and into the opening in the `lower pole piece 32. Any convenient means for holding the encoding attachment in place under a typewriter may be employed, such as clamps, not shown, which attach to the sides or the bottom of the typewriter, or the encoding attachment can be attached to a base plate, not shown, having indents thereon for locatng the typewriter feet so that when it is desired to use the encoding attachment the typewriter is in proper operative position relative thereto. Any suitable means for locating the encoding attachment may be employed. This can vary with the typewriter with Awhich it is to be used. However, in practically every case, there is room underneath the typewriter for an encoding attachment to be piaced where it will be actuated Whenever one of the typewriter keys is depressed whereby a lever is operated from the key which eventually moves the type character selected toward the typewriter carriage.

With a typewriter having forty-four keys, six lines or channels are more than suicient to provide a separate code for each of the forty-four characters since there are 26 possibilities which permits handling sixty-four different situations.

Referring now to FIGURE 4 which is a circuit diagram of an embodimen-t of Ithe invention there may be seen six encoding channels. A separate wire 71, 72, 73, 74,

75, 76, comprises each encoding channel. Each one of the six wires extends along the groove provided by the narrow portion of the electrical insulating board 50. One end of each one of the wires is grounded and the other end is connected to the emitter of a transistor respectively 81, 82, 83 S4, S5 and 86. Each one of the transistors has its collector to a source of operating potential 87 through a resistor respectively 91, 92, 93, 94, and 96. Each one of the voltage dividers respectively 101, 102, 103, 104, 105 and 106, is connected to the source of operating potential and serves to provide a biasing voltage for the bases of the respective transistors 31 through 86. An output terminal respectively 101A through 106A is connected to the collector of each one of the transistors 81 through 86.

The code representation is indicated by the presence or absence of an output voltage on terminals 101 through 106. For example: assuming it is desired to encode the presence of letter G by the presence of a voltage on output terminal 102A and by the absence of a voltage on the other output terminals, then the conductor 72 would be wrapped for a single turn, 72A, around the bobbin through which the one of the pins 36, will pass when the G key on the typewriter is actuated. The pin, by effectively bridging the upper and lower pole pieces with the bobbin Ktherebetween serves to suddenly increase the magnetic ux of the eld which couples the single turn 72A around the bobbin whereby a voltage is induced and a current tlows through the conductor 72. This will be amplified by the transistor 82 and will appear at the output 102. In the example given previously, for encoding the letter A, a pulse is required on lines 71, 73 and 76 when the A key is depressed, and this can be etfectuated by turns 71B, 72B, 76B. Thus, a single turn may be taken around the bobbin by one or more of the lines 71 through 76 depending upon the desired representation when the key on the typewriter which actuates the pin passing through that bobbin is depressed.

A preferred arrangement for utilizing the output pulses from the encoding unit is shown in FIGURE 5. Each one of the terminals 101 through 106 is connected to the input of another flip-flop circuit respectively 111 through 116. Thus the ones of output terminals which are actuated when a key on the typewriter is depressed will cause corresponding ones of the ip-flops, 111 through 116, to be driven to their set state. Outputs are taken from each one of the ip-ilops and are respectively applied to and gate circuits 121 through 126. The outputs from all the flip-flops, 111 through 116, are also applied to an or circuit 127. Thus any one or more of the flip-flops which are driven to their seit states by the outputs from the terminals 101A through 106A cause the or" circuit to provide an output. This output is applied to a delay circuit 123. The delay circuit after a shout delay applies an output to a strobing circuit 130 and also to a second delay circuit 132. The strobing circuit 130 applies a second required output to all of the and gates 121 through whereby those of the and gates connected to ip-flops which are in their set state can provide an output. In this manner the output signals are all standardized and appear simultaneously instead of at slightly dilfering times as can be the case in view of the fact that the number of turns and thereby the inductance of these various lines wound around ,the bobbins is different for each line. The second delay circuit 132 applies its output to reset all the Hip-flops 111 through 116.

The encoding arrangement in accordance with lthis invention is suitable for use with different typewriters. It is an extremely exible device and aside from wear on the pins, which is negligible, can last indefinitely. To change the code it is only necessary Ito remove the small electrical board 50 and to re-run the six wire lines linking the bobbins. Rapid changes among several relatively standard codes can be accomplished by providing several complete boards, each wired for a different code. The

auxiliary circuit shown in FIGURE 5 can be housed in a small box external .to the typewriter and connected to fthe encoder by cable. In an embodiment of the invention which was built, an Alnico 5 magnet was employed and provided a suicient to generate about 5 millivolts output per turn of wire around the bobbin.

There has been accordingly described herein a novel, useful, simple and inexpensive encoding device for enabling an electrical code to be derived from a typewriter.

I claim:

1. An encoding attachment for association with a typewriter wherein the actuation of each different typewriter key produces a dilerent code output, said encoding attachment comprising a plurality of nonmagnetic bobbins, a different one of which is associated with a different one of said typewriter keys, a plurality of conductive lines selectively wound upon each said bobbin in accordance with a predetermined code representation desired for the typewriter key associated with a bobbin, and magnetic means for inducing a voltage in the windings on a bobbin responsive to the actuation of its associated typewriter key whereby said plurality of conductors present a voltage pattern which is the electrical encoding of the character yrepresented by a typewriter key.

2. Encoding apparatus as recited in claim 1 wherein said magnetic means comprises means for establishing a magnetic afield transversely to .the windings on all of said plurality of bobbins, and means responsive to the operation of a typewriter key to alter the magnetic eld applied to a bobbin associated with said actuated typewriter key.

3. An encoding attachment for association with a typewriter wherein the actuation of each different typewriter Ikey produces a diierent electrical code output, said encoding attachment comprising a plurality of cylindrical coil bobbins having hollow centers, each of said coil bobbins being associated with a different one of said typewriter keys, a plurality of metal pins a different one of which is associated with a different one of said bobbins, a plurality of conductors, selected ones of which are wound on said fbobbins in accordance with a predetermined code representation desired for the key of the typewriter with which said bobbin is associated, an elongated upper pole shoe having an aligned plurality of apertures therethrough, said aligned apertures extending in the direction of elongation at said upper pole shoe, an elongated lower pole shoe spaced lfrom said upper pole shoe and having a plurality of apertures a different one of which is aligned with a diierent one of the apertures in said upper pole shoe, said plurality of lbobbins being disposed between said upper and lower pole shoes, each of said bobbins having its hollow center aligned with different two opposite apertures in said upper and lower pole shoes, means for supporting each pin of said plurality of pins for reciprocal insertion through the center of a bobbin in response to the operation of the typewriter key with which a bobbin is associated, and means for establishing a magnetic iield between said upper and lower pole shoes whereby upon reciprocal insertion of a pin into the aligned aperture of an upper and lower pole shoe and the center of the bobbin therebetween a unique voltage pattern is achieved on said plurality of conductors. t

4. An encoding attachment for a typewriter which is to .be actuated upon the actuation of a typewriter key to produce an electrical code uniquely indicative of the key which has been actuated, said encoding attachment comprising for each typewriter key a -pin made of a material having a magnetic reluctance which is lower than that of the air, nonmagnetic coil form means, a plurality of wire conductors, predetermined ones of which are wrapped around said coil form means with at least one turn in accordance with the desired code representation for a key, means for establishing a magnetic -field through said coil form mean-s, means for inserting a pin in the one of said coil form means in response to the actuation of a typewriter key with which said pin and coil form means are associated whereby a voltage pattern is established in said conductors uniquely representative of the key which was depressed.

5. An encoding device suitable for actuation by the keys of a typewriter comprising, associated with each key desired to be encoded a separate pin, means for supporting said pins for reciprocal movement, U shaped magnetic means co-extensive with said means for supporting said pins, said U shaped magnetic means having a pair of opposed apertures in the arms of said U into which a different one of said pins may be reciprocably inserted, means for connecting said U shaped magnetic means and said means for supportin-g said pins to electuate alignment of each of the pairs of holes in `the arms of said U with a different one of said pins, a plurality of bobbins having hollow centers, positioned between the arms said U shaped magnetic means with a dilerent one of said ibobbinfs having its hollow center aligned with a different one of the pairs of holes in said U shaped magnetic means for enabling each one of said pins to pass into the holes in said U shaped magnetic means adjacent thereto and through one of said bobbins, a plurality of wires, said wires being wound on a different one of said bobbins in accordance with the desired code representation, said pins .being positioned with respect to said typewriter to be actuated selectively -in response to the actuation of a diiferent one of said typewriter keys.

References Cited by the Examiner UNITED STATES PATENTS 2,343,404 3/1944 Doty 178-81 2,408,754 10/ 1946 Bus 17'8-181 2,997,703 8/ 1961 Powell 340--347 3,017,459 l/ 1962 Saykay 178--26 3,119,996 1/ 1964 Comstock 340-345 NEIL C. READ, Primary Examiner. ROBERT H. ROSE, Examiner.

A. I. DUNN, T. A. ROBINSON, Assistant Examiners. 

1. AN ENCODING ATTACHMENT FOR ASSOCIATION WITH A TYPEWRITER WHEREIN THE ACTUATION OF EACH DIFFERENT TYPEWRITER KEY PRODUCES A DIFFERENT CODE OUTPUT, SAID ENCODING ATTACHMENT COMPRISING A PLURALITY OF NONMAGNETIC BOBBINS, A DIFFERENT ONE OF WHICH IS ASSOCIATED WITH A DIFFERENT ONE OF SAID TYPEWRITER KEYS, A PLURALITY OF CONDUCTIVE LINES SELECTIVELY WOUND UPON EACH SAID BOBBIN IN ACCORDANCE WITH A PREDETERMINED CODE REPRESENTATION DESIRED FOR THE TYPEWRITER KEY ASSOCIATED WITH A BOBBIN, AND MAGNETIC MEANS FOR INDUCING A VOLTAGE IN THE WINDINGS ON A BOBBIN RESPONSIVE TO THE ACTUATION OF ITS ASSOCIATED TYPEWRITER KEY WHEREBY SAID PLURALITY OF CONDUCTORS PRESENT A VOLTAGE PATTERN WHICH IS THE ELECTRICAL ENCODING OF THE CHARACTER REPRESENTED BY A TYPEWRITER KEY. 